Supporting body for a grinding tool and method of producing a supporting body

ABSTRACT

A supporting body for a grinding tool, the supporting body including an abrasive pad having a preferably circumferential supporting surface for an abrasive material, particularly a superabrasive material. The supporting body consisting substantially of a composite material which is free of abrasive material and consists of a plurality of layers of a natural fiber material which are arranged one atop the other and are connected to each other by plastic, preferably phenolic resin. The natural fiber material preferably is a cotton fabric or paper, and the supporting body includes a first, preferably cylindrical or hollow cylindrical body and at least one additional, preferably cylindrical or hollow cylindrical body, in which the bodies are connected, preferably adhesively bonded, to each other.

BACKGROUND OF THE INVENTION

The invention concerns a support body for a grinding tool, and agrinding tool having such a support body and an abrasive layer which hasabrasive means, in particular superabrasive means, and which is arrangedon a preferably circumferential support surface of the support body. Theabrasive layer is formed from a continuous abrasive ring or individualabrasive segments. The invention further concerns a method of producinga support body as noted above, and a method of producing a grinding toolhaving such a support body.

Support bodies for grinding tools should be as far as possible stable,light and with a damping action in particular in so-called centerlessgrinding tools.

It is known from the state of the art to produce support bodies from aphenolic moulding material by hot pressing and hardening. Then eithermixtures of synthetic resin, fillers and superabrasive means are pressedhot on to those supports or ceramic superabrasive layers are adhesivelybonded in place. A support body produced in that way is light and dampsvibrations in the grinding process so that wear of the layers incomparison for example with layers with aluminium supports in grindinguse is reduced and the surface quality of the ground components isimproved, this being manifested by a lower degree of roughness, lesserbreak-outs and the absence of chatter marks.

It will be noted, however, that those support bodies suffer from thedisadvantage that a relatively great uncontrolled wastage occurs in theproduction of the supports, and only a limited spectrum of supportbodies in regard to the dimensions thereof can be produced. In addition,cracking occurs in the grinding operation. The maximum working highestspeed is limited to about 63 m/s.

U.S. Pat. No. 2,069,116 discloses a grinding tool having a support bodyformed from layers of a fibrous layer material. The grinding tool isproduced jointly with the support body in a press of fixed dimensions,wherein the individual layers of the layer material have to besuccessively laid in the press. That manufacturing procedure is highlytime-consuming. In addition, only grinding tools of the fixed size canbe produced by means of the press so that it is not possible to producea grinding tool of differing dimensions.

It is further known from the state of the art to produce support bodiesfrom a carbon fibre-reinforced plastic. That material makes it possibleto produce light and at the same time dimensionally stable supportbodies. However that involves very complicated production and very highmanufacturing costs.

SUMMARY OF THE INVENTION

The object of the present invention is to at least partially overcomethe disadvantages of the state of the art and to provide a support bodywhich is lighter and improved in relation thereto as well as a grindingtool having such a support body. A further object is to provide a methodof producing a support body and a grinding tool having such a supportbody, in which the method is in particular distinguished in that supportbodies and grinding tools of differing dimensions can be flexiblyproduced, more specifically in a short time and at reasonable productioncosts.

The support body substantially comprises an abrasive means-freecomposite material comprising a plurality of mutually superposed layersof a natural fibre material and which are connected together by plastic,preferably phenolic resin.

The term ‘abrasive means’ in connection with the present invention isused to denote hard material grains which are used to achieve removal ofmaterial from a workpiece. In that respect, natural grain materials(flint, quartz, corundum, emery, granite, natural diamond) and syntheticgrain materials (corundums, silicon carbides, chromium oxides, cubicboron nitride, diamonds) are differentiated.

The term ‘superabrasive means’ is used to denote professional diamondand cubic boron nitride.

If there are no abrasive or superabrasive means present in a materialthen they are of an abrasive means-free nature in accordance with thepresent invention.

Abrasive means-free composite materials comprising a plurality ofmutually superposed layers of a natural fibre material which areconnected together by plastic, preferably phenolic resin, wherein thenatural fibre material is a cotton fabric or paper, are known from thetechnical field of the production of electrical and thermal insulationcomponents for machine and equipment construction—in the case of cottonfabric—as hard cotton fabric and—in the case of paper—in the form ofhard papers.

In comparison with the support bodies known from the state of the artand comprising a phenolic moulding material the support body accordingto the invention has an approximately 30% higher flexural breakingstress, an elongation at break which is about three times greater and ahigher elasticity, and is about 15% lighter. Higher operational speedsare possible, for example 125 m/s and more.

In addition, in the production of the support body or a grinding toolhaving such a support body, no or markedly reduced wastage occurs.

When an abrasive layer mixture for producing an abrasive ring is pressedon to the support body, a lower pressure is required for that purpose inthe pressing operation. The grinding tool is markedly easier to removefrom the mould as the support body does not expand after the hotpressing operation. Pressing without a flange is also easier, therebysubsequently giving a potential saving in a machining operation.

The use of the composite material also makes it possible to producesupport bodies in a wider range of sizes. Thus, support bodies forexample up to a diameter of 1050 mm and a height of 100 mm can bereadily produced.

The composite material further has the advantage that it can be moreeasily machined with carbide metal. Usually expensive tools with PCDcutting edges have to be used in comparison therewith for machining thematerials used in the state of the art. Furthermore the compositematerial can be very well combined with other materials like for examplecarbon fibre reinforced plastic, glass fibre reinforced plastic, Al orsteel, for example by glueing or screwing.

Advantageously, the composite material used in the present invention isthermosetting, that is to say it is no longer deformable after setting.

By virtue of the fact that the support body has a first, preferablycylindrical or hollow-cylindrical body and at least one further,preferably cylindrical or hollow-cylindrical body, wherein the bodiesare connected together, preferably by glueing, it is possible in aflexible fashion to construct light support bodies of complex shapes, ascould be achieved in the state of the art only with carbonfibre-reinforced plastic, but in a markedly shorter time and at markedlylower cost.

According to advantageous embodiments the natural fibre material is acotton fabric or paper.

In regard to its physical properties it has proven to be advantageous ifthe composite material is of a density of 1.0 to 2.0 g/cm³, preferably1.4 g/cm³ (for example measured in accordance with the testing standardISO 1183) and/or has a water absorption of 1.5 to 7.5%, preferably 2.4%or 5.2% (for example measured in accordance with the testing standardISO 62).

In regard to the thermal properties it has proven to be advantageous ifthe composite material has a length extension coefficient of 20 to40×10⁻⁶ K⁻¹, preferably 30×10⁻⁶ K⁻¹ (for example measured in accordancewith the testing standard DIN 51045) and/or thermal conductivity of 0.1to 0.3 W/mK, preferably 0.2 W/mK (for example measured in accordancewith the testing standard DIN 52612).

The temperature of use can be continuously or temporarily 110° C. or180° C.

In regard to the mechanical properties, it is appropriate if thecomposite material has a compressive strength at 23° C. of 200 to 400N/mm², preferably 300 N/mm² or 320 N/mm² (for example measured inaccordance with the testing standard ISO 604) and/or a flexural strengthat 23° C. of 50 to 150 N/mm², preferably 100 N/mm² or 135 N/mm² (forexample measured in accordance with the testing standard ISO 178) and/ora modulus of elasticity (from a bending test) of 6000 to 8000 N/mm²,preferably 7000 N/mm² (for example measured in accordance with thetesting standard ISO 178) and/or a tensile strength of 50 to 150 N/mm²,preferably 80 N/mm² or 120 N/mm² (for example measured in accordancewith the testing standard ISO 527) and/or a splitting force of 1500 to3500 N, preferably 1900 N or 3000 N (for example measured in accordancewith the testing standard DIN 53463).

In regard to the electrical properties, the composite material can havea tracking resistance CTI 100 (for example measured in accordance withthe testing standard IEC 112) and/or an electrical dielectric strength(perpendicular) of 1.5 KV/3 mm or 10 KV/3 mm (for example measured inaccordance with the testing standard IEC 243-1) and/or an electricaldielectric strength (parallel) of 1.0 KV/25 mm or 10 KV/25 mm (forexample measured in accordance with the testing standard IEC 243-1).

According to a preferred embodiment of the invention, the support bodyhas at least one side surface which is separate from the support surfacefor the abrasive layer and at which a layer of the composite material isarranged flat.

It is further appropriate if the support body has a central couplingregion, preferably with a central bore, for connection to a rotary drivefor rotating the support body or a grinding tool formed therewith aboutan axis of rotation extending through the coupling region and/or thesupport body is of a substantially rotationally symmetricalconfiguration.

It has proven to be advantageous if the first and the at least onefurther body are cylindrical or hollow-cylindrical bodies which areconnected together at side surfaces, preferably in which axes ofsymmetry of the bodies are substantially congruent. The support bodiesor grinding tools which can be produced in that way are particularlywell suited for example for grinding camshafts.

It has further proven to be desirable if the support body has an adaptorfor connecting the support body or a grinding tool formed therewith to arotary drive connected, preferably glued to at least one of the bodies,preferably wherein the adaptor substantially comprises a metal and/or isof a substantially hollow-cylindrical configuration.

In this connection, it is appropriate if the support body has a centralbore, and the adaptor is at least region-wise arranged in the centralbore. Preferably, the adaptor extends only over a part of the length ofthe central bore, and particularly preferably the central bore has afunnel-shaped insertion opening. A funnel-shaped insertion opening makesit easier to clamp the support body.

A grinding tool has a support body according to the invention and anabrasive layer which has abrasive means, in particular superabrasivemeans, and which is arranged on the preferably circumferential supportsurface of the support body. Preferably, the abrasive layer is formedfrom a continuous abrasive ring or individual abrasive segments.

Furthermore, a method of producing a support body for a grinding tool isprovided. The support body includes a preferably circumferential supportsurface for an abrasive layer having abrasive means, in particularsuperabrasive means, and substantially comprises an abrasive means-freecomposite material comprising a plurality of mutually superposed layersof a natural fibre material which are connected together by plastic,preferably phenolic resin, preferably wherein the natural fibre materialis a cotton fabric or paper. The abrasive means-free composite materialis provided in the form of a plate in a first method step and in asecond method step a preferably cylindrical or hollow-cylindrical bodyis cut out of the plate with predetermined dimensions preferably bywater jet cutting or by means of a band saw.

According to an advantageous configuration, in the course of the secondmethod step at least one further, preferably cylindrical orhollow-cylindrical body is cut out of the plate with predetermineddimensions and connected to the first body, preferably by adhesive.

In this connection, it is appropriate if the first and the at least onefurther body is cylindrical or hollow-cylindrical bodies, the bodiesbeing connected together at side surfaces, preferably wherein axes ofsymmetry of the bodies are brought substantially into congruentrelationship.

It has proven to be advantageous if in a third method step the body orbodies is or are re-worked, preferably by cutting machining and/orbalancing and/or by fitting a central bore.

It has proven to be desirable if at least one of the bodies in a furthermethod step which follows the second method step or the third methodstep is connected to an adaptor for connecting the support body or agrinding tool formed therewith to a rotary drive, preferably byadhesive. Preferably, the adaptor substantially comprises a metal and/oris of a substantially hollow-cylindrical configuration.

In addition, protection is claimed for a method of producing a grindingtool having a support body which includes a preferably circumferentialsupport surface for an abrasive layer having abrasive means, inparticular superabrasive means, and substantially comprises an abrasivemeans-free composite material comprising a plurality of mutuallysuperposed layers of a natural fibre material, which are connectedtogether by plastic, preferably phenolic resin. The natural fibrematerial is a cotton fabric or paper, and an abrasive layer which hasabrasive means, in particular superabrasive means and which is arrangedon the preferably circumferential support surface of the support body.Preferably, the abrasive layer is formed from a continuous abrasive ringor individual abrasive segments. Firstly, a support body preferablyproduced by means of the method for production of the support body isprovided, and then an abrasive layer having abrasive means, preferablysuperabrasive means, is arranged on a preferably circumferential supportsurface of the support body, preferably by pressing thereon and/oradhesive bonding, and preferably the abrasive layer is formed from acontinuous abrasive ring or individual abrasive segments.

BRIEF DESCRIPTION OF THE DRAWINGS

Further details and advantages of the invention will be described morefully hereinafter by means of the specific description with reference tothe drawings in which:

FIG. 1a is a diagrammatic side view of a support body,

FIG. 1b is a diagrammatic cross-sectional view along section plane 24 ofthe support body of FIG. 1 a,

FIG. 2 is a diagrammatic side view of a grinding tool according to afirst preferred embodiment,

FIG. 3a is a photograph of a grinding tool according to a secondpreferred embodiment as a side view,

FIG. 3b is a microscope image of a cross-sectional surface of thecomposite material used in the grinding tool according to the secondpreferred embodiment,

FIGS. 4a and 4b show microscope images of a further composite materialwhich is preferably used of a side surface (FIG. 4a ) and across-sectional surface,

FIG. 5 shows a diagrammatic view by means of a flow chart of a method ofproducing a support body and a cutting tool, and

FIGS. 6a and 6b show a further grinding tool as a diagrammaticperspective view (FIG. 6a ) and a diagrammatic cross-sectional view(FIG. 6b ).

DETAILED DESCRIPTION OF THE INVENTION

FIGS. 1a and 1b show a support body 1 for a grinding tool 2 (see alsoFIG. 2) which is substantially rotationally symmetrical and includes acircumferential support surface 3 for an abrasive layer 5 havingabrasive means 4, in particular superabrasive means.

The support body 1 substantially comprises an abrasive means-freecomposite material 6 comprising a plurality of mutually superposedlayers 7 of a natural fibre material connected together by plastic 8.That is diagrammatically indicated in the view on an enlarged scale ofthe portion in FIG. 1b . The plastic 8 can be a hardened syntheticresin, preferably phenolic resin.

Directly adjacent layers 7 can be at a very small spacing relative toeach other and even at least region-wise touch. The layers 7 areoriented substantially parallel to side surfaces.

Two embodiments have proven to be particularly advantageous in relationto the composite material 6.

In the first embodiment the natural fibre material is a cotton fabric.In that case the composite material 6 is of a density of 1.4 g/cm³ andhas water absorption of 2.4%. In addition the composite material 6 has alength extension coefficient of 30×10⁻⁶ K⁻¹ and a thermal conductivityof 0.2 W/mK. And finally the composite material 6 has a compressivestrength at 23° C. of 320 N/mm², a flexural strength at 23° of 100N/mm², a modulus of elasticity of 7000 N/mm², a tensile strength of 80N/mm² and a splitting force of 3000 N.

In the second embodiment the natural fibre material is paper. In thatcase the composite material 6 is of a density of 1.4 g/cm³ and has waterabsorption of 5.2%. In addition the composite material 6 has a lengthextension coefficient of 30×10⁻⁶ K⁻¹ and a thermal conductivity of 0.2W/mK. And finally the composite material 6 has a compressive strength at23° C. of 300 N/mm², a flexural strength at 23° of 135 N/mm², a modulusof elasticity of 7000 N/mm², a tensile strength of 120 N/mm² and asplitting force of 1900 N.

The support body 1 has two oppositely disposed side surfaces 9 which areseparate from the support surface 3 for the abrasive layer 5 and atwhich a respective layer 7 of the natural fibre material is arrangedflat (see also FIG. 3a ).

The support body 1 includes a central coupling region 10 having acentral bore 11 for connection to a rotary drive for rotating thesupport body 1 or a grinding tool 2 formed therewith about an axis ofrotation 12 extending through the coupling region 10. The axis ofrotation 12 extends through the centre 25 of the central bore 11 and isoriented substantially normal to the side surfaces 9.

The dimensions of the support body 1 can be characterised by itsdiameter 17, its thickness 18 and the diameter 19 of the central bore11.

The grinding tool 2 shown in FIG. 2 includes a support body 1 and anabrasive layer 5 having abrasive means 4, in particular superabrasivemeans, arranged on the circumferential support surface 3 of the supportbody 1. The abrasive means 4 is diagrammatically indicated in theenlarged portion. The abrasive means 4 is embedded in a binding, forexample a ceramic binding.

The abrasive layer 5 can be formed from a continuous abrasive ring or,as indicated in the lower region of the grinding tool 2, individualabrasive elements 13.

In the grinding tool 2 shown in FIG. 3a the support body 1 has a sidesurface 9 which is separate from the support surface 3 for the abrasivelayer 5 and at which a layer 7 of a natural fibre material in the formof a cotton fabric is arranged flat. That can be seen in particular fromthe enlarged view in which the fabric structure comprising substantiallyperpendicularly crossing fabric threads with weft and warp threads 26can be seen.

To improve the rotary characteristic of the grinding tool 2 the supportbody 1 can have balancing bores 22 and/or a step 23.

FIG. 3b shows a microscope image of a cross-sectional surface of thecomposite material used in the grinding tool 2 of the second preferredembodiment. It is possible clearly to see the layers 7 of the cottonfabric, which are arranged in mutually superposed relationship in thedirection of the axis of rotation 12 and which are made up of individualcotton fibres 26.

FIGS. 4a and 4b show microscope images of a further composite materialwhich is preferably used, more specifically a side surface (FIG. 4a )and a cross-sectional surface (FIG. 4b ). In this case the natural fibrematerial is paper. FIG. 4a shows individual paper fibres 27 arrangedstochastically within a layer 7. FIG. 4b shows a structure comprisingmutually superposed layers 7.

Particularly preferred embodiments of the method of producing a supportbody and the method of producing a grinding tool are illustrated byreference to the flow chart shown in FIG. 5.

In the method 14 of producing a support body 1 in a first method step 15the abrasive means-free composite material 6 comprising a plurality ofmutually superposed layers 7 of a natural fibre material, that areconnected together by plastic 8, preferably phenolic resin, is providedin the form of a plate.

In a second method step 16 a body is cut out of the plate withpredetermined dimensions 17, 18, 19 (see FIGS. 1a and 1b ), preferablyby water jet cutting or by means of a band saw. In the case of thesupport body 1 shown in FIG. 1 the body is a round disc.

In a third method step 20 the body is re-worked, preferably by cuttingmachining and/or balancing.

That method 14 can be expanded to constitute a method 21 of producing agrinding tool 2 insofar as, in a further method step 28, an abrasivelayer 5 having abrasive means 4, preferably superabrasive means, isarranged on a preferably circumferential support surface 3 of thesupport body 1, preferably by pressing and/or adhesive bonding thereon,preferably wherein the abrasive layer 5 is formed from a continuousabrasive ring or individual abrasive segments 13.

The third method step 20 can optionally also be carried out only afterthe abrasive layer 5 is arranged on the support surface 3 of the supportbody 1.

FIGS. 6a and 6b show a grinding tool 2 having a support body 1 which ismade up of five hollow-cylindrical bodies 29, 30, 31, 32, 33, whereinthe bodies 29, 30, 31, 32, 33 are glued together at side surfaces 9. Theaxes of symmetry 12 of the bodies 29, 30, 31, 32, 33 are substantiallycoincident. Depending on the respective shape of the support body 1 itis also possible to use another number of cylindrical orhollow-cylindrical bodies 29, 30, 31, 32, 33.

The support body 1 has an adaptor 34 for connecting the support body 1or the grinding tool 2 formed therewith to a rotary drive which isadhesively secured to the bodies 32 and 33. The adaptor 34 can also beconnected to more than two or only to one of the bodies 29, 30, 31, 32,33, in particular in dependence on the stiffness to be achieved for thegrinding tool 2.

The adaptor 34 can substantially comprise a metal and, as in theillustrated case, can be substantially hollow-cylindrical.

As in the illustrated case the adaptor 34 can have bores 37 forreceiving fixing means, by way of which the adaptor 34 can be connectedto a machine spindle.

The support body 1 has a central bore 11. The adaptor 34 is arranged inthe central bore 11, with the adaptor 34 extending only over a part ofthe length 35 of the central bore 11. The central bore 11 has afunnel-shaped insertion opening 36.

A respective abrasive disc 5 is circumferentially arranged on the bodies29 and 31.

For producing the support body 1 it is appropriate in a first methodstep 15 to provide a plate of a thickness 18 and in a second method step16 to cut out of the plate with predetermined dimensions 17, 18, 19,three cylindrical or hollow-cylindrical bodies 30, 32 and 33, preferablyby water jet cutting or by means of a band saw.

It is also appropriate in the course of the first method step 15 toprovide a further plate of a differing thickness 18 and in the course ofthe second method step 16 to cut out of the plate two cylindrical orhollow cylindrical bodies 29 and 31, of predetermined dimensions 17, 18,19, preferably by water jet cutting or by means of a band saw.

In the course of the second method step 16 the bodies 29, 30, 31, 32, 33are connected together after they have been cut out of the plates atside surfaces 9, wherein axes of symmetry 12 of the bodies 29, 30, 31,32, 33 are brought substantially into coincident relationship.

In a third method step 20 the bodies 29, 30, 31, 32, 33 are re-worked bycutting machining, in particular to impart predetermined dimensions tothe central bore 11.

In a further method step the bodies 32, 33 are connected to the adaptor34.

1. A support body for a grinding tool which includes a preferablycircumferential support surface for an abrasive layer having abrasivemeans, in particular superabrasive means, wherein the support bodysubstantially comprises an abrasive means-free composite materialcomprising a plurality of mutually superposed layers of a natural fibrematerial which are connected together by plastic, preferably phenolicresin, preferably wherein the natural fibre material is a cotton fabricor paper, wherein the support body has a first, preferably cylindricalor hollow-cylindrical body and at least one further, preferablycylindrical or hollow-cylindrical body, wherein the bodies are connectedtogether, preferably adhesively bonded.
 2. The support body according toclaim 1, wherein the composite material is of a density of 1.0 to 2.0g/cm³, preferably 1.4 g/cm³ and/or has a water absorption of 1.5 to7.5%, preferably 2.4% or 5.2%.
 3. The support body according to claim 1,wherein the composite material has a length extension coefficient of 20to 40×10⁻⁶ K⁻¹, preferably 30×10⁻⁶ K⁻¹ and/or thermal conductivity of0.1 to 0.3 W/mK, preferably 0.2 W/mK.
 4. The support body according toclaim 1, wherein the composite material has a compressive strength at23° C. of 200 to 400 N/mm², preferably 300 N/mm² or 320 N/mm² and/or aflexural strength at 23° C. of 50 to 150 N/mm², preferably 100 N/mm² or135 N/mm² and/or a modulus of elasticity of 6000 to 8000 N/mm²,preferably 7000 N/mm² and/or a tensile strength of 50 to 150 N/mm²,preferably 80 N/mm² or 120 N/mm² and/or a splitting force of 1500 to3500 N, preferably 1900 N or 3000 N.
 5. The support body according toclaim 1, wherein the support body has at least one side surface which isseparate from the support surface for the abrasive layer and at which alayer of the natural fibre material is arranged flat.
 6. The supportbody according to claim 1, wherein the support body has a centralcoupling region, preferably with a central bore, for connection to arotary drive for rotating the support body or a grinding tool formedtherewith about an axis of rotation extending through the couplingregion and/or the support body is of a substantially rotationallysymmetrical configuration.
 7. The support body according to claim 1,wherein the first and the at least one further body are cylindrical orhollow-cylindrical bodies which are connected together at side surfaces,preferably wherein axes of symmetry of the bodies are substantiallycongruent.
 8. The support body according to claim 1, wherein the supportbody has an adaptor for connecting the support body or a grinding toolformed therewith to a rotary drive connected, preferably glued to atleast one of the bodies, preferably wherein the adaptor substantiallycomprises a metal and/or is of a substantially hollow-cylindricalconfiguration.
 9. The support body according to claim 8, wherein thesupport body has a central bore and the adaptor is at least region-wisearranged in the central bore, preferably wherein the adaptor extendsonly over a part of the length of the central bore, particularlypreferably wherein the central bore has a funnel-shaped insertionopening.
 10. A grinding tool having the support body according to claim1 and an abrasive layer which has abrasive means, in particularsuperabrasive means, and which is arranged on the preferablycircumferential support surface of the support body, preferably whereinthe abrasive layer is formed from a continuous abrasive ring orindividual abrasive segments.
 11. A method of producing a support bodyfor a grinding tool, wherein the support body includes a preferablycircumferential support surface for an abrasive layer having abrasivemeans, in particular superabrasive means, and substantially comprises anabrasive means-free composite material comprising a plurality ofmutually superposed layers of a natural fibre material, which areconnected together by plastic, preferably phenolic resin, wherein thenatural fibre material is a cotton fabric or paper, wherein the abrasivemeans-free composite material is provided in the form of a plate in afirst method step and in a second method step a preferably cylindricalor hollow-cylindrical body is cut out of the plate with predetermineddimensions preferably by water jet cutting or by means of a band saw.12. The method according to claim 11, wherein, in the course of thesecond method step, at least one further, preferably cylindrical orhollow-cylindrical body is cut out of the plate with predetermineddimensions and connected to the first body, preferably by adhesive. 13.The method according to claim 12, wherein the first and the at least onefurther body is cylindrical or hollow-cylindrical bodies, the bodiesbeing connected together at side surfaces, preferably wherein axes ofsymmetry of the bodies are brought substantially into congruentrelationship.
 14. The method according to claim 11, wherein in a thirdmethod step the body or bodies is or are re-worked, preferably bycutting machining and/or balancing and/or by fitting a central bore. 15.The method according to claim 11, wherein at least one of the bodies ina further method step which follows the second method step or the thirdmethod step is connected to an adaptor for connecting the support bodyor a grinding tool formed therewith to a rotary drive, preferably byadhesive, preferably wherein the adaptor substantially comprises a metaland/or is of a substantially hollow-cylindrical configuration.
 16. Amethod of producing a grinding tool having a support body which includesa preferably circumferential support surface for an abrasive layerhaving abrasive means, in particular superabrasive means, andsubstantially comprises an abrasive means-free composite materialcomprising a plurality of mutually superposed layers of a natural fibrematerial, which are connected together by plastic, preferably phenolicresin, preferably wherein the natural fibre material is a cotton fabricor paper, and an abrasive layer which has abrasive means, in particularsuperabrasive means and which is arranged on the preferablycircumferential support surface of the support body, preferably whereinthe abrasive layer is formed from a continuous abrasive ring orindividual abrasive segments, wherein firstly a support body produced bythe method according to claim 11 is provided and then an abrasive layerhaving abrasive means, preferably superabrasive means, is arranged on apreferably circumferential support surface of the support body,preferably by pressing thereon and/or adhesive bonding, preferablywherein the abrasive layer is formed from a continuous abrasive ring orindividual abrasive segments.